1. Field of the Invention
The present invention generally relates to communication devices and, more particularly, to communication devices that have a plurality of modems.
2. Background of the Invention
Many modern communication devices incorporate multiple modems to facilitate communication over more than one network. For example, some mobile stations, such as those available from Motorola, Inc. of Schaumburg, Ill., have begun to offer mobile stations capable of communicating over CDMA and iDEN networks. (Motorola and iDEN are trademarks of Motorola, Inc. in the United States, other countries, or both).
Other examples of communication devices having multiple modems can include mobile stations that communicate over mobile phone network(s) as well as over one or more short range wireless networks such as an IEEE 802 wireless network or a Bluetooth® wireless network. Mobile stations typically include Bluetooth modems for communicating with wireless peripheral devices such as earpieces and the like. The various modems within the communication device often operate concurrently and independently of one another. This functionality allows the user to engage in a telephone conversation on the mobile station while also sending or receiving data in one or more other formats. For instance, the user can browse the Internet, communicate data files, and communicate via electronic mail.
Several considerations arise when more than one modem is used concurrently within a mobile station. One consideration is the increased power needed to drive the mobile station. Each additional modem increases the power needed by the device thereby placing a larger burden on the battery. The current draw that occurs when more than one modem is active at the same time can, in some cases, be so significant that the useful life of the battery is reduced.
Another consideration is thermal energy. The use of multiple modems concurrently, particularly in light of the increased transmission rates and longer duty cycles of selected modems, can result in the generation of a significant amount of thermal energy. The thermal energy generated by the mobile station can, in some cases, rapidly deplete the battery.